MERCEDES-BENZ M-Class 2013 W166 Repair Manual

Emergency Tensioning Devices, seat
belt force limiter
G
WARNING
Pyrotechnic Emergency Tensioning Devices
that have been deployed must be renewed.
For your safety, when disposing of Emergency
Tensioning Devices, always observe the
safety instructions. These are available from
any authorized Mercedes-Ben zCenter.
The PRE-SAFE ®
system has electrically
operated reversible pre-tensioners that do
not require replacement after activation.
! If the front-passenger seat is not
occupied, do not engage the seat belt
tongue in the buckle on the front-
passenger seat. Otherwise, the Emergency
Tensioning Device could be triggered in the
event of an accident.
X In order to ensure that the pyrotechnic
Emergency Tensioning Devices have not
been triggered, always have the seat belts
checked after an accident.
If the Emergency Tensioning Devices have
been triggered, they must be replaced.
The fron tseat belts and the outer seat belts
in the rear are equipped with Emergency
Tensioning Devices and belt force limiters.
The ETDs on the driver's and front-passenger
seat consist of pyrotechnic belt buckle
tensioners and belt anchor tensioners that
are triggered together. The belt buckle
tensioner is mounted on the B-pillar and the
belt anchor installing is mounted on the side
of the seat. After deploying, both tensioners
must always be replaced.
The ETDs tighten the seat belts in an accident,
pulling them close against the body.
The ETDs do not correct incorrect seat
positions or incorrectly fastened seat belts.
The ETDs do not pull vehicle occupants back
towards the backrest.
When triggered, seat belt force limiters help
to reduce the peak forc eexerted by the seat
belt on the vehicle occupant. The belt force limiters for the front seats are
synchronized with the front ai
rbags, which
take on a part of the deceleration force. This
results in the force exerted on the occupant
being distributed ove ragreater area.
The ETDs can only be activated when:
R the ignition is switched on.
R the restraint systems are operational; see
"SRS warning lamp" (Y page 43).
R the belt tongue is engaged in the buckle on
each of the lap-shoulder belts in the front.
R the front-passenger seat is occupied and
the belt tongue is engaged in the buckle on
the front-passenger side
The ETDs on the outside seats in the rear
compartment are triggered independently of
the lock status of the seat belts.
The ETDs are triggered depending on the type
and severity of an accident:
R if, in the event of a head-on or rear-end
collision, the vehicle decelerates or
accelerates rapidly in a longitudinal
direction during the initial stages of the
impact
R if, in the event of a side impact, on the side
opposite the impact the vehicle
decelerates or accelerates rapidly in a
lateral direction
R if, in certain situations where the vehicle
overturns, the system determines that it
can provide additional protection
If the ETDs are deployed, you will hear a bang,
and a small amount of powder may also be
released. Only in rare cases will the bang
affect your hearing. The powder that is
released generally does not constitute a
health hazard. The 001FSRS warning lamp
lights up. Occupant safety
59Safety Z

Children in the vehicle
Child restraint systems
Important safety notes G
WARNING
According to accident statistics, children are
safe rwhen properly restrained in the rear
seating positions than in the front seating
position. Thus, we strongly recommend that
children be placed in the rear seats whenever
possible. Regardless of seating position,
children 12 years old and under must be
seated and properly secured in an appropriate
infant restraint, toddler restraint, or booster
seat recommended for the size and weight of
the child.
The infant or child restraint must be properly
secured with the vehicle's seat belt, the seat
belt and top tether strap, or lower anchors and
top tether strap, fully in accordance with the
child seat manufacturer's instructions.
Occupants, especially children, should always
sit as upright as possible, wear the seat belt
properly and use an appropriately sized infant
restraint, toddler restraint, or booster seat
recommended for the size and weight of the
child.
Children can be killed or seriously injured by
an inflating air bag. Note the following
important information when circumstances
require you to place a child in the front
passenger seat:
R Your vehicle is equipped with air bag
technology designed to deactivate the front
passenger front air bag in your vehicle
when the system senses the weight of a
typical 12-month-old child or less along
with the weight of a standard appropriate
child restraint on the front passenger seat.
R For children larger than the typical
12-month-old child, the front passenger
front air bag may or may not be activated.
Always make sure the 001A001Cindicator
lamp is illuminated, indicating that the front
passenger front air bag is deactivated. R
Ac hild in a rear-facing child restraint on the
front passenger seat will be seriously
injured or even killed if the front passenger
front air bag inflates in a collision which
could occur under some circumstances,
even with the air bag technology installed
in your vehicle. The only means to
completely eliminate this risk is to never
place a child in a rear-facing child restraint
in the front seat. We therefore strongly
recommend that you always place a child
in a rear-facing child restraint in a backseat.
R If you must install a rear-facing child
restraint on the front passenger seat
because circumstances require you to do
so, make sure the 001A001Cindicator
lamp is illuminated, indicating that the front
passenger front air bag is deactivated.
Should the 001A001Cindicator lamp not
illuminate or go out while the restraint is
installed, please chec kinstallation.
Periodically check the 001A001Cindicator
lamp while driving to make sure the 001A
001C indicator lamp is illuminated. If the
001A001Cindicator lamp goes out or
remains out, do not transport a child on the
front passenger seat until the system has
been repaired.
Ac hild in a rear-facing child restraint on the
front passenger seat will be seriously
injured or even killed if the front passenger
front air bag inflates.
R If you have to place a child in a forward-
facing child restraint on the front passenger
seat, move the seat as far back as possible,
use the proper child restraint
recommended for the age, size and weight
of the child, and secure child restraint with
the vehicle's seat belt according to the
child seat manufacturer's instructions. G
WARNING
If the child restraint system is not fitted
correctly on a suitable seat, it may not fulfil
its protective function. In the event of an
accident, sharp braking or a sudden change 60
Children in the vehicleSafety

in direction, the child may not be held
securely. The child could thus be seriously or
even fatally injured. For this reason, when
fitting a child restraint system, observe the
manufacturer's installation instructions and
the correct use of the child restraint system.
Child restraint systems should preferably be
fitted on the rear seats .The child is generally
better protected there.
The entire base of the child restraint system
must always rest on the seat cushion.
Therefore, never place objects, e.g. a cushion,
under the child restraint system.
Only use child restraint systems with the
original cover designed for them. Only replace
damaged covers with genuine covers.
We recommend that you use the child
restraint systems which have been
recommended for Mercedes-Benz. G
WARNING
Infants and small children should never share
a seat belt with another occupant. In the event
of an accident, they could be crushed
between the occupant and seat belt.
Ac hild's risk of serious or fatal injuries is
significantly increased if the child restraints
are not properly secured in the vehicle and/
or the child is not properly secured in the child
restraint.
Children that are too large for a child restraint
must travel in seats using normal seat belts.
Position the shoulder belt across the chest
and shoulder, not face or neck.Ab ooster seat
may be necessary to achieve proper seat belt
positioning for children over 41 lb (18 kg) until
they reach a height where a lap-shoulder belt
fits properly without a booster.
When the child restraint is not in use, remove
it from the vehicle or secure it with the seat
belt to prevent the child restraint from
becoming a projectile in the event of an
accident. G
WARNING
When leaving the vehicle, always remove the
SmartKey from the ignition lock. Always take
the SmartKey with you and lock the vehicle.
Do not leave children unattended in the
vehicle, even if they are secured in a child
restraint system, or with access to an
unlocked vehicle. Achild's unsupervised
access to a vehicle could result in an accident
and/or serious personal injury. The children
could:
R injure themselves on parts of the vehicle
R be seriously or fatally injured through
excessive exposure to extreme heat or cold
R injure themselves or cause an accident with
vehicle equipment that can be operated
even if the SmartKey is removed from the
ignition lock or removed from the vehicle,
such as seat adjustment, steering wheel
adjustment, or the memory function
If children open a door, they could injure other
persons or get out of the vehicle and injure
themselves or be injured by following traffic.
Do not expose the child restraint system to
direct sunlight. The child restraint system's
metal parts, for example, could become very
hot, and the child could be burned on these
parts. G
WARNING
Do not carry heavy or hard objects in the
passenger compartment or cargo
compartmentu nless they are firmly secured
in place.
Unsecured or improperly positioned cargo
increases a child's risk of injury in the event
of
R strong braking maneuvers
R sudden changes of direction
R an accident
Further informatio nonsecure stowage of
loads can be found under "Loading
guidelines". Children in the vehicle
61Safety Z

If an infant or child is traveling in the vehicle:
R Secure the child with a child or infant seat
restraint system appropriate to the age and
weight of the child.
R Make sure that the infant or child is
properly secured at all times while the
vehicle is in motion.
Mercedes-Benz recommends that you always
properly secure all infants and childre nwith
a child or infant seat restraint system for the
trip.
The use of seat belts and infant and child
restraint systems is required by law in:
R all 50 states
R U.S. territories
R the Distric tofColumbia
R all Canadia nprovinces
Infants and children must always be seated in
an appropriate infant or child restraint system
recommended for the size and weight of the
child .The infant or child restraint system
must be properly secured in accordance with
the manufacturer's instructions.
All infant or child restraint systems must meet
the following standards:
R U.S. Federal Motor Vehicle Safety
Standards 213 and 225
R CanadianM otor Vehicle Safety Standards
213 and 210.2
An information label on the child restraint
system indicates whether it meets these
standards. This information is also provided
in the installation instructions supplied with
the child restraint system.
Always read and follow the manufacturer's
instructions when using an infant or child
restraint system or booster seat.
Observe the warning labels in the vehicle
interior or on the infant or child restraint. Special seat belt retractor G
WARNING
If you release the seat belt when driving, the
special seat belt retractor is deactivated.
The released seat belt cannot be engaged
again while driving, because the inertia reel
pulls in the seat belt a small distance. The
child restraint system is no longer properly
secured. There is an increased risk of serious
injury or even fatal injury.
Always keep the seat belt of the activated
special seat belt retractor engaged when
driving.
All seat belts except the driver's seat belt are
equipped with a special seat belt retractor.
When activated, the special seat belt
retractor ensures that the seat belt will not
slacken once the child restraint system has
been secured.
Installing a child restraint system:
X Always comply with the manufacturer's
installation instructions.
X Pull the seat belt smoothly from the seat
belt retractor.
X Engage the seat belt tongue in the belt
buckle.
Activating the special seat belt retractor:
X Pull the seat belt out fully and let the seat
belt retractor retract it again.
While the seat belt is retracting, you should
hear a ratcheting sound. The special seat
belt retractor is activated.
X Push down on the child restraint system to
take up any slack.
Removing a child restraint system/
deactivating the special seat belt retractor:
X Always comply with the manufacturer's
installation instructions.
X Press the seat belt release button and
guide the belt tongue to the belt outlet.
The special seat belt retractor is
deactivated. 62
Children in the vehicleSafety

LATCH-type (ISOFIX) child seat anchors
in the rear
G
WARNING
Children that are too large for a child restraint
must travel in seats usin gnormal seat belts.
Position shoulder belt across the chest and
shoulder, not face or neck.
Ab ooster seat may be necessary to achieve
proper seat belt positioning for children over
41 lb (18 kg) until they reach a height where
a lap/shoulder belt fits properly without a
booster.
Install the child restraint system in
accordance with the manufacturer's
instructions.
Attach the child restraint system to both
securing rings.
An incorrectly installed child restraint system
could come loose during an accident and
seriously or even fatally injure the child.
Child restraint systems or child seat securing
rings that are malfunctioning or damaged as
the result of a collision must be replaced.
! When installing the child restraint system,
make sure that the seat belt for the middle
seat does not get trapped. The seat belt
could otherwise be damaged. X
Install the LATCH-type (ISOFIX) child seat
securing system. Comply with the
manufacturer's instructions when
installing.
ISOFIX is a standardized securing system for
specially designed child restraint systems on the rear seats. Securing rings
0002for two
LATCH-type (ISOFIX) child restraint systems
are installed on the left and right of the rear
seats.
Secure child restraint systems without a
LATCH-type (ISOFIX) child seat securing
system using the seat belts in the vehicle.
When installing child restraint systems, you
must observe the manufacturer's installation
instructions.
Top Tether Top Tether anchorages
G
WARNING
Always lock the rear seat backrests in their
upright position when the rear seats are
occupied by passengers. Lock the rear seat
backrests in their upright position before
installing the Top Tether straps or when the
cargo compartment is not in use. Make sure
that rear seat backrest sare secured properly
by pushing and pulling on the seat backrests.
If the seat backrest is not locked properly, the
seat backrest could fold forward. The child
restraint system is no longer supported
properly or held in position and can no longer
fulfill its function. This could cause serious or
even fatal injuries. Children in the vehicle
63Safety Z

Top Tether provides an additional connection
between a child restraint system, secured
with a LATCH-type (ISOFIX) child seat mount,
and the rear seat. This helps reduce the risk
of injury even further.
The Top Tether anchorages are located on the
rear side of the rear seat backrests.
X Move head restraint 001Fupwards.
X Install the LATCH-type (ISOFIX) child
restraint system with Top Tether. Comply
with the manufacturer's installation
instructions when doing so.
X Route Top Tether belt 001Dunder head
restraint 001Fbetween the two head restraint
bars.
X Guide Top Tether belt 001Ddownwards
between cargo compartment cover 0002and
rear seat backrest 0003.
X Hook Top Tether hook 001Cof Top Tether belt
001D into Top Tether anchorage 001E.Ensure that:
R
Top Tether hook 001Cis hooked into Top
Tether anchorage 001Eas shown.
R Top Tether belt 001Dis not twisted.
R Top Tether belt 001Dis routed between rear
seat backrest 0003and cargo
compartment cover 0002if cargo
compartment cover 0002is installed.
R Top Tether belt 001Dis routed between the
rear seat backrest 0003and the cargo net
if the cargo net is installed.
X Tension Top Tether belt 001D.Comply with
the manufacturer's installation
instructions when doing so.
X Move head restraint 001Fback down again
slightly if necessary (Y page 106). Make
sure that you do not interfere with the
correc trouting of Top Tether belt 001D. Child-proof locks
Important safety notes G
WARNING
When leaving the vehicle, always remove the
SmartKey from the ignition lock. Always take
the SmartKey with you and lock the vehicle.
Do not leave children unattended in the
vehicle, even if they are secured in a child
restraint system, or with access to an
unlocked vehicle. Achild's unsupervised
access to a vehicle could result in an accident
and/or serious personal injury. The children
could:
R injure themselves on parts of the vehicle
R be seriously or fatally injured through
excessive exposure to extreme heat or cold
R injure themselves or cause an accident with
vehicle equipment that can be operated
even if the SmartKey is removed from the
ignition lock or removed from the vehicle,
such as seat adjustment, steering wheel
adjustment, or the memory function 64
Children in the vehicleSafety

If childre
nopen a door, they could injure other
persons or get out of the vehicle and injure
themselves or be injured by following traffic.
Do not expose the child restraint system to
direct sunlight .The child restraint system's
metal parts, for example, could become very
hot, and the child could be burned on these
parts.
Child-proof locks for the rear doors G
WARNING
Children could open a rear door from inside
the vehicle. This could result in serious
injuries or an accident. Therefore, when
children ride in the rear always secure the rear
doors with the child-proof locks. You secure each door individually with the
child-proof locks on the rear doors. Adoor
secured with a child-proof lock cannot be
opened from inside the vehicle. When the
vehicle is unlocked, the door can be opened
from the outside.
X To activate: press the child-proof lock
lever up in the direction of arrow 0002.
X Make sure that the child-proof locks are
working properly.
X To deactivate: press the child-proof lock
lever down in the direction of arrow 0003.Override feature for the rear side
windows G
WARNING
When children ride on the vehicle's rear seats,
activate the override switch. Otherwise, the
children could be injured, e.g. by trapping
themselves in the rear side window. X
To activate/deactivate: press button0002.
If indicator lamp 0003is lit, operation of the
rear side windows is disabled. Operation is
only possible using the switches in the
driver's door. If indicator lamp 0003is off,
operation is possible using the switches in
the rear compartment. Driving safety systems
Overview of driving safety systems
In this section, you will find information about
the following driving safety systems:
R ABS (Anti-lock BrakingSystem)
(Y page 66)
R BAS (Brake AssistSystem) (Y page 67)
R BAS PLUS ( BrakeAssist System PLUS)
(Y page 67)
R COLLISION PREVENTION
ASSIST(Y page 68)
R ESP ®
(Electronic StabilityProgram)
(Y page 71)
R EBD ( electronic brake force distribution)
(Y page 73)
R ADAPTIVE BRAKE( Ypage 73) Driving safety systems
65Safety Z

R
PRE-SAFE ®
Brake (Y page 73)
R STEER CONTROL (Y page 75)Important safety notes
If you fail to adapt your driving style or
become distracted, the driving safety
systems can neither reduce the risk of
accident nor override the laws of physics.
Driving safety systems are merely aids
designed to assist driving. You are
responsible for the distance to the vehicle in
front, for vehicle speed and for braking in
good time. Always adapt your driving style to
suit the prevailing road and weather
conditions and maintain asafe distance from
the vehicle in front. Drive carefully.
i The driving safety systems described only
work as effectively as possible when there
is adequate contact between the tires and
the road surface. Please pay special
attention to the note son tires,
recommended minimu mtire tread depths,
etc. (Y page 398).
In wintry driving conditions, always use
winter tires (M+S tires) and if necessary,
snow chains. Only in this way will the
driving safety systems described in this
section work as effectively as possible. ABS (Anti-lock Braking System)
Important safety notes i
Observe the "Importan tsafety notes"
sectio n(Ypage 66). G
WARNING
If ABSi s faulty, the wheels could lock when
braking. The steerability and braking
characteristics may be severely impaired.
Additionally, further driving safety systems
are deactivated. There is an increased danger
of skidding and accidents. Drive on carefully. Have ABS checked
immediately at a qualified specialist
workshop.
When ABS is malfunctioning, other systems,
including driving safety systems, will also
become inoperative. Observe the information
on the ABS warning lamp (Y page 318) and
display messages which may be shown in the
instrument cluster (Y page 283).
ABS regulates brake pressure in such a way
that the wheels do not lock when you brake.
This allows you to continue steering the
vehicle when braking.
ABS works from a speed of about 5 mph
(8 km/h) upwards, regardless of road-surface
conditions. ABS works on slippery surfaces,
even if you only brake gently.
The yellow 0019ABS warning lamp in the
instrument cluster lights up when the ignition
is switched on. It goes out when the engine is
running.
Braking X
If ABS intervenes: continue to depress the
brake pedal vigorously until the braking
situation is over.
X To make a full brake application:
depress the brake pedal with full force.
If ABS intervenes when braking, you will feel
a pulsing in the brake pedal.
The pulsating brake pedal can be an
indication of hazardous road conditions, and
functions as a reminder to take extra care
while driving.
Off-road ABS An ABS system specifically suited to off-road
terrain is activated automatically once the off-
road program is activated on:
R
vehicles without the ON&OFFROAD
package (Y page 248)
R vehicles with the ON&OFFROAD package
(Y page 248) 66
Driving safety systemsSafety

At speeds below 20 mph (30 km/h), the front
wheels lock cyclically during braking .The
digging-in effect achieved in the process
reduces the stopping distance on off-road
terrain. This limits steering capability. BAS (Brake Assist System)
i Observe the "Important safety notes"
section (Y page 66). G
WARNING
If BAS is malfunctioning, the braking distance
in an emergency braking situation is
increased. There is a risk of an accident.
In an emergency braking situation, depress
the brake pedal with full force. ABS prevents
the wheels from locking.
BAS operates in emergency braking
situations. If you depress the brake pedal
quickly, BAS automatically boosts the braking
force, thus shortening the stopping distance.
The brakes will function as usual once you
release the brake pedal. BAS is deactivated. BAS PLUS (Brake Assist System
PLUS)
i Observe the "Important safety notes"
section (Y page 66).
BAS PLUS is only available in vehicles
equipped with DISTRONIC PLUS.
For BAS PLUS to assist you when driving, the
radar sensor system must be:
R activated (Y page 277)
R operational
With the help of the radar sensor system, BAS
PLUS can detect obstacles that are in the
path of your vehicle for an extended period of
time.
If the radar sensor system is malfunctioning,
BAS PLUS will not be available. The brake
system is still available with complete brake
boosting effect and BAS. BAS PLUS provides braking assistance in
hazardous situations at speeds greater than
4 mph (7 km/h).
At speeds of up to approximately 40 mph
(70 km/h), BAS PLUS can also detect
stationary objects. Examples of stationary
objects are stopped or parked vehicles.
To prevent a front-end collision, BAS PLUS
calculates the brake force necessary if:
R
you approach an obstacle, and
R BAS PLUS has detected arisk of collision
At as pee dless than 20 mp h(30 km/h) : if
you depress the brake pedal, BASP LUS is
activated. The increase in brake pressure will
be carried out at the last possible moment.
At a speed greater than 20 mph
(30 km/h):ify ou depress the brake pedal
sharply, BAS PLUS automatically raises the
brake pressure to a value adapted to the
traffic situation.
If BAS PLUS demands particularly high
braking force, preventative passenger
protection measures (PRE-SAFE ®
) are
activated simultaneously.
X Keep the brake pedal depressed until the
emergency braking situation is over.
ABS prevents the wheels from locking.
BAS PLUS is deactivated and the brakes
function as usual, if:
R you release the brake pedal.
R there is no longer any danger of a rear-end
collision.
R no obstacle is detected in front of your
vehicle.
If you have activated DSR (Y page 246), BAS
PLUS is likewise deactivated. G
WARNING
BAS PLUS cannot always clearly identify
objects and complex traffic situations. BAS
PLUS cannot intervene in these cases. There
is a risk of an accident.
Always pay careful attention to the traffic
situation and be ready to brake. Driving safety systems
67Safety Z

In particular, the detection of obstacles can
be impaired if:
R
there is dirt on the sensors or anything else
covering the sensors.
R snow or heavy rain
R interference by other radars ources
R there are strong radar reflections, for
example in parking garages
R a narrow vehicle traveling in front, e.g. a
motorbike
R a vehicle traveling in front on a different line
relative to the center of your vehicle G
WARNING
BAS PLUS does not react:
R to people or animals
R to oncoming vehicles
R to crossing traffic
R when cornering
As aresult, BAS PLUS may not intervene in all
critical situations. There is a risk of an
accident.
Always pay careful attention to the traffic
situation and be ready to brake.
Following damage to the fron tend of the
vehicle, have the configuratio nand operation
of the rada rsensors checked at a qualified
specialist workshop. This also applies to
collisions at low speeds where there is no
visible damage to the fron tofthe vehicle. COLLISION PREVENTION ASSIST
General notes COLLISION PREVENTION ASSIST consists of
Adaptive Brake Assist and the distance
warning function, which are described in the
following. Distance warning function Important safety notes
i
Observe the "Important safety notes"
section (Y page 66). G
WARNING
The distance warning function does not react:
R to people or animals
R to oncoming vehicles
R to crossing traffic
R when cornering
Thus, the distance warning function cannot
provide a warning in all critical situations.
There is a risk of an accident.
Always pay careful attention to the traffic
situation and be ready to brake.
The distance warning function cannot always
clearly identify objects and complex traffic
situations.
In such cases, the distance warning function
may:
R give an unnecessary warning
R not give a warning
Always pay careful attention to the traffic
situation and do not rely solely on the
distance warning function.
Function
X To activate/deactivate: activate or
deactivate the distance warning function in
the on-board computer (Y page 272).
When the distance warning function is
activated, the multifunction display shows
the 0003 symbol, as long as the HOLD
function is not switched on (Y page 207). On
vehicles with Active Parking Assist, the
0003 symbol is displayed when Pis engaged
or you are driving faster than 22 mph
(35 km/h).
The distance warning function can help you
to minimize the risk of a front-end collision
with a vehicle ahead or reduce the effects of
such a collision. If the distance warning 68
Driving safety systemsSafety